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QUASI-PERMUTATION REPRESENTATIONS OF ALTERNATING AND SYMMETRIC GROUPS

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Acta Mathematica Scientia 2007年第2期27卷 297-300页

作者： Houshang Behravesh Mohammad Hossein jafari Department of Mathematics University of Urmia UrmiaIran Department of Mathematics University of Tabriz TabrizIran

The quantities c（G）, q（G） and p（G） for finite groups were defined by H. Behravesh. In this article, these quantities for the alternating group An and the symmetric group Sn are calculated. It is shown that c（G... 详细信息

关键词： Quasi-permutation representations alternating groups symmetric groups character theory

Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery

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Petroleum Science 2019年第6期16卷 1387-1402页

作者： Sajjad Mahmoudi Arezou jafari Soheila Javadian Department of Petroleum Engineering Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran Department of Physical Chemistry Faculty of Basic ScienceTarbiat Modares UniversityP.O.Box 14115-175TehranIran

Recently,nanoparticles have been used along with surfactants for enhancing oil *** the recent studies show that oil recovery is enhanced using nanoparticle/surfactant solutions,some effective parameters and mechanisms involved in the oil recovery have not yet been ***,the temperature effect on the stability of nanoparticle/surfactant solutions and ultimate oil recovery has been studied in this work,and the optimal concentrations of both SiO2 nanoparticle and surfactant(sodium dodecyl sulfate)have been determined by the Central Composite Design *** addition,the simultaneous effects of parameters and their interactions have been *** of the stability of the injected solutions indicates that the nanoparticle concentration is the most important factor affecting the solution *** surfactant makes the solution more stable if used in appropriate concentrations below the *** to the micromodel flooding results,the most effective factor for enhancing oil recovery is temperature compared to the nanoparticle and surfactant ***,in floodings with higher porous medium temperature,the oil viscosity reduction is considerable,and more oil is *** addition,the surfactant concentration plays a more effective role in reservoirs with higher *** other words,at a surfactant concentration of 250 ppm,the ultimate oil recovery is improved about 20%with a temperature increase of 20°***,when the surfactant concentration is equal to 750 ppm,the temperature increase enhances the ultimate oil recovery by only about 7%.Finally,the nanoparticle and surfactant optimum concentrations determined by Design-Expert software were equal to 46 and 159 ppm,*** is worthy to note that obtained results are validated by the confirmation test.

关键词： Enhanced heavy oil recovery Nanoparticle Surfactant Temperature High salinity brine Stability Micromodel Experimental design

Hydrothermal and entropy generation specifications of a hybrid ferronanofluid in microchannel heat sink embedded in CPUs

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Chinese Journal of Chemical Engineering 2021年第4期34卷 27-38页

作者： Amin Shahsavar Majid jafari Pouyan Talebizadehsardari Davood Toghraie Department of Mechanical Engineering Kermanshah University of TechnologyKermanshahIran Metamaterials for Mechanical Biomechanical and Multiphysical Applications Research GroupTon Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh CityVietnam Department of Mechanical Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahrIran

The objective of this numerical work is to evaluate the first law and second law performances of a hybrid nanofluid flowing through a liquidcooled microchannel *** waterbased hybrid nanofluid includes the Fe_(3)O_(4)and carbon nanotubes(CNTs)*** heatsink includes a microchannel configuration for the flow field to gain heat from a processor placed on the bottom of the *** effects of Fe_(3)O_(4)concentration(φFe_(3)O_(4))>CNT concentration(φCNT)and Reynolds number(Re)on the convective heat transfer coefficient,CPU surface temperature,thermal resistance,pumping power,as well as the rate of entropy generation due to the heat transfer and fluid friction is *** results indicated higher values of convective heat transfer coefficient,pumping power,and frictional entropy generation rate for higher values of Re,Fe_(3)O_(4)andφ*** increasing Re,Fe_(3)O_(4)and uCNT,the CPU surface temperature and the thermal resistance decrease,and the temperature distribution at the CPU surface became more *** achieve the maximum performance of the studied heatsink,applying the hybrid nanofluid with low Fe_(3)O_(4)andφCNT was suggested,while the minimum entropy generation was achieved with the application of nanofluid with highφFe_(3)O_(4)andφCNT.

关键词： Liquid-cooled heatsink Hydrothermal aspects Irreversibility Hybrid nanofluid Carbon nanotube Fe_(3)O_(4)

Nanoparticles assisted microwave radiation:Fluid-rock interactions in oil reservoirs

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Petroleum Science 2021年第6期18卷 1797-1812页

作者： Hamzeh Shamsi Armandi Arezou jafari Reza Gharibshahi Faculty of Chemical Engineering Tarbiat Modares UniversityTehranIran

Recently,many researchers have focused on the usage of electromagnetic waves in oil production and well stimulation,but so far the effect of these waves on the fluid and rock interaction and its simultaneous effect with nanoparticles have not been ***-rock interaction is one of the most important factors affecting fluid distribution in the *** this study,the oil reservoir rock wettability alteration under electromagnetic heating and the presence of nanoparticles has been *** nanoparticles of TiO_2,Fe_(3)O_(4),and TiO_2/Fe_(3)O_(4)have been ***_2 nanoparticles are commercially available,and the other mentioned nanoparticles are synthesized via a co-precipitation *** acid has been used to modify surfaces of nanoparticles and stabilize them in water as the base ***,the adsorption of the nanoparticles on the rock surface has been *** the next step,the amount of oil outflow from the rock has been measured and reported as the external fluid *** this process,the nanoparticle performance in wettability alteration was investigated using pH and inductively coupled plasma(ICP)*** better understand the governing mechanisms,oil viscosity was measured by mixing the oil with nanoparticles and put under *** results reveal that the microwave has a great ability to reduce oil contact angle with carbonate *** the presence of0.2 wt%Fe_(3)O_(4)nanoparticles,the contact angle was reduced from 155°to 19°after 28 min of irradiation,indicating strong rock ***,microwave irradiation on Fe_(3)O_(4)nanofluid extracts75%of the oil from the *** microwave radiation,the pH of the nanofluid increases and hence,more nanoparticles are adsorbed on the rock which subsequently causes more rock *** viscosity change results prove that there is an optimal irradiation time of 5 min in which oil viscosity reduces from 481 cP to 410 cP and then increases to 827

关键词： Microwave radiation Wettability alteration Nanoparticle adsorption Rock-fluid interaction

Evaluation of the Relationship between Blocking Patterns and Duration of Spring Frost Waves:The Case of Iran

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Journal of Meteorological Research 2020年第3期34卷 586-600页

作者： Farzaneh jafari HOMBARI Gholamreaza BARATI Mohammad MORADI Department of Physical Geography Faculty of Earth SciencesUniversity of Shahid BeheshtiTehran ***Iran Iran Meteorological Organization Tehran ***Iran

In order to evaluate the effects of blocking patterns on the duration of frost waves across Iran,the minimum daily temperatures of 60 weather stations were collected from 20 March 1968 to 21 June *** findings,which were obtained based on the distribution tables of reported temperatures and their frequency variation graphs,resulted in identifying 114 frost *** obtained the daily weather maps at 500 hPa from NCEP/NCAR during the peak days of durable frosts,and it was revealed that the formation of low pressures over 20°-70°E and the dominant southwest-northeast troughs at 500 hPa facilitated the influx of cold air from both eastern Europe and central Siberia toward Iran,leading to the average frost duration of 12.4 ***,low-pressure centers appeared in a dipole pattern in northern Iran over Caspian Sea and created durable frosts with an average duration of 15.4 *** effect of omega shaped pattern of the geopotential height on durable frosts demonstrated a sharp difference with two recent patterns leading to the frost occurrence with a 13.3-day duration ***,the slow speed of cold western currents in the rex type of blocking from 30°to 50°N caused durable frosts of 14.3 ***,we found a specific reduction in the frequency of blocking patterns,which has occurred in the past four ***,the blocking and non-blocking patterns cause long-and short-duration frosts over Iran,respectively.

关键词： blocking patterns durable frosts spring season Iran

A drought resistance index to select drought resistant plant species based on leaf water potential measurements

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Journal of Arid Land 2019年第4期11卷 623-635页

作者： SayedJamaleddin KHAJEDDIN SayedHamid MATINKHAH Zahra jafari Department of Natural Resources Isfahan University of Technology

The water deficit in arid and semi-arid regions is the primary limiting factor for the development of urban greenery and forestation. In addition, planting the species that consume low levels of water is useful in arid and semi-arid regions that have poor water management measures. Leaf water potential(Ψ) is a physiological parameter that can be used to identify drought resistance in various species. Indeed, Ψ is one of the most important properties of a plant that can be measured using a pressure chamber. Drought avoiding or drought resistant species have a lower Ψ than plants that use normal or high levels of water. To determine drought resistance of species that are suitable for afforestation in arid urban regions, we evaluated twenty woody species in the Isfahan City, central Iran. The experimental design was random split-split plots with five replications. The species were planted outdoor in plastic pots and then subjected to treatments that consisted of two soil types and five drip irrigation regimes. To evaluate the resistance of each species to drought, we used the Ψ and the number of survived plants to obtain the drought resistance index(DRI). Then, cluster analysis, dendrogram, and similarity index were used to group the species using DRI. Result indicates that the evaluated species were classified into five groups:(1) high water consuming species(DRI>–60 MPa);(2) above normal water consuming species(–60 MPa≥DRI>–90 MPa);(3) normal water consuming species(–90 MPa≥DRI>–120 MPa);(4) semi-drought resistant species(–120 MPa≥DRI>–150 MPa);and(5) drought resistant species(DRI≤–150 MPa). According to the DRI, Salix babylonica L., Populus alba L., and P. nigra L. are high water consuming species, Platanus orientalis L. and Albizia julibrissin Benth are normal water consuming species, and Quercus infectoria Oliv. and Olea europaea L. can be considered as drought resistant species.

关键词： drought resistant species drought resistance index forestation leaf water potential water deficit

Numerical analysis of rock fracturing by gas pressure using the extended finite element method

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Petroleum Science 2015年第2期12卷 304-315页

作者： Majid Goodarzi Soheil Mohammadi Ahmad jafari Department of Civil Engineering and Geoscience University of Newcastle School of Civil Engineering University of Tehran School of Mining Engineering University of Tehran

High energy gas fracturing is a simple approach of applying high pressure gas to stimulate wells by gen- erating several radial cracks without creating any other damages to the wells. In this paper, a numerical algorithm is proposed to quantitatively simulate propagation of these fractures around a pressurized hole as a quasi-static phenomenon. The gas flow through the cracks is assumed as a one-dimensional transient flow, governed by equations of conservation of mass and momentum. The fractured medium is modeled with the extended finite element method, and the stress intensity factor is calculated by the simple, though sufficiently accurate, displacement ex- trapolation method. To evaluate the proposed algorithm, two field tests are simulated and the unknown parameters are determined through calibration. Sensitivity analyses are performed on the main effective parameters. Considering that the level of uncertainty is very high in these types of engineering problems, the results show a good agreement with the experimental data. They are also consistent with the theory that the final crack length is mainly determined by the gas pressure rather than the initial crack length produced by the stress waves.

关键词： Gas fracturing Numerical modeling Extended finite element Fracture mechanics

Temperature-dependent development of Neoseiulus barked （Acari： Phytoseiidae） on Tetranychus urticae （Acari： Tetranychidae） at seven constant temperatures

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Insect Science 2012年第2期19卷 220-228页

作者： Shahriar jafari Yaghoub Fathipour Farid Faraji Department of Entomology Faculty of Agriculture Tarbiat Modares University Tehran Iran MITOX Consultants Amsterdam The Netherlands

The effect of seven constant temperatures of 15, 20, 25, 27, 30, 35 and 37℃ on developmental time ofNeoseiulus barkeri Hughes were determined in laboratory conditions under 65% - 5% RH and a photoperiod of 12 ： 12 （L ： D） h on nymphal stages of Tetranychus urticae Koch. Total developmental time of females （from egg to adult emergence） at the above-mentioned temperatures was 26.59, 14.43, 6.32, 5.64, 4.59, 3.98 and 4.67 days, respectively. Developmental rate of the N. barkeri increased as temperature increased from 15 to 35℃, but declined at 37℃. A linear and two nonlinear models were fitted to developmental rate of immature stages ofN. barkeri to predict the developmental rate as a function of temperature, as well as to estimate the thermal constant （K） and critical temperatures （i.e., Tmin, Topt and Tmax）. The estimated values of the Tmin and K for total developmental time using the linear model were 12.07℃ and 86.20 degree-days （DD）, respectively. The Trnin and Tmax estimated by the Sharpe-Schoolfield-Ikemoto （SSI） model were 11.90℃ and 37.41℃, respectively. The estimated Topt for overall immature stage development ofN. barkeri by the Lactin and SSI models were 33.89℃ and 24.51℃, respectively. Based on the biological criteria of model evaluation, the linear and SSI models were found to be the best models for describing the developmental rate of overall immature stages of N. barkeri and estimating the temperature thresholds.

关键词： Neoseiulus barkeri temperature thresholds temperature-dependent development Tetranychus urticae thermal constant

Experimental investigation on the effect of surface characterization of electrodes on the gas bubble dynamics in electrolyte flow and performance of FLA batteries by using PIV

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Chinese Journal of Chemical Engineering 2021年第5期34卷 30-39页

作者： Saeed Nahidi Iraj jafari Gavzan Seyfolah Saedodin Mahmoud Salari Department of Mechanical Engineering Semnan UniversitySemnanIran Department of Mechanical Engineering Imam Hossein UniversityTehranIran

In the flooded lead_acid batteries(FLAB),gas bubbles are initially formed on the surface of the electrodes,which are produced by electrochemical reactions,and then released into the *** the present investigation,the effect of surface characterization of electrodes of FLAB on the gas bubble dynamic parameters in the electrolyte flow at different charging/discharging rates(C-rates)are studied utilizing particle image velocimetry(PIV)*** results show that the capacity of FLAB have a linear behavior due to changes in each of the two parameters of the surface characterization of electrodes and the *** all State of charges(SOCs)of FLAB cells in different tests,increasing average roughness(Ra)and average wavelength of the roughness(λa)in the electrode surfaces,results in an increase in average bubble diameter and bubble rising ***,a sharp decrease in the void fraction of bubbles within the electrolyte was observed due to the increment inλa and ***,the effect of the rising movement of gas bubbles within the electrolyte on the average electrolyte velocity pattern in the gap between the electrodes by changing the surface characterization of electrodes are investigated in detail.

关键词： Particle image velocimetry (PIV) Flooded lead_acid batteries (FLAB) Insoluble gas bubble Electrochemical reactions Surface characterization of electrodes